Molecular Characterisation of Aeromonas Species Isolated from Water and Selected Food Molecular Characterisation of Aeromonas Species Isolated from Water and Selected Food

Citation

Rajab, Mohd Kamil
(1999)
Molecular Characterisation of Aeromonas Species Isolated from Water and Selected Food Molecular Characterisation of Aeromonas Species Isolated from Water and Selected Food.
Masters thesis, Universiti Putra Malaysia.

Abstract / Synopsis

Three species of Aeromonas; A. hydrophila (60 isolates), A. sobria (34
isolates) and A. caviae(113isolates) were isolated from beef, milk,
freshwater prawns, fish, and water from fishpond. A. hydrophila was
predominant in fish and freshwater prawn, whereas A. caviae was
predominant in the milk and water samples. A. sobria was only found in
freshwater prawn, water and fish samples. The results of the study indicated
that all the five different sources examined were potential vector for
Aeromonas in Malaysia. The percentage of antibiotic resistant among
Aeromonas species was varying according to its origin. A. hydrophila was
more resistant towards ampicillin, bacitracin, carbenicillin and erythromycin.
Most of the A. sobria isolates were resistant to ampicillin, bacitracin,
carbenicillin and streptomycin and A. caviae was resistant to ampicillin,
bacitracin and carbenicillin. The multiple antibiotic resistance (MAR) index of
A. hydrophila, A. sobria and A. caviae ranged between 0.08 to 0.66, 0.16 to
0.66, and 0 (zero) to 0.5, respectively. Hence, the MAR indexing of the
Aeromonas strains showed that more than 90% originated from high were detected in 50 of the 60 A. hydrophila isolates and 35 plasmid profiles
were identified. The plasmid size ranged from 1.4 to 7.0 MDa. Plasmids of
1.4 to 4.1 MDa were detected in 28 of the 34 A. sobria isolates tested, while
six isolates were found to be plasmidless. Their plasmid patterns were
grouped into 18 patterns. Twenty-one plasmid patterns were found from A.
caviae with plasmid sizes ranging from 1.4 to 8.0 MDa. In general,
Aeromonas species under study harboured high number of plasmids. The
plasmid analysis indicated the presence of more than one clone with the
same antibiotic resistance patterns. The data obtained indicated that the
samples sources tested form a reservoir for multiple-resistant and plasmid
containing Aeromonas species in the study area. The RAPO-PCR was
performed to characterise the Aeromonas spp. by using three random
primers (GEN26003, GEN26007, and GEN26010). Among the Aeromonas
spp., A. hydrophila was found to be differentiated by the three primers
distinctively. Primer GEN26003 was the most suitable primer to differentiate
the isolates. The three primers generated polymorph isms in all 207 strains of
Aeromonas species tested, producing bands ranging from 0.24 to 4.5 Kb.
The RAPO profiles revealed a wide variability and no correlation with the
source of isolation. In addition, the RAPO data suggested that the
Aeromonas strains might have originated from diverse sources.